【Objective】 To analyse the efficacy and possible mechanism of treating children bronchiolitis caused by respiratory syncytial virus (RSV) and post-infection inflammation of the air passage by budesonide atomizing inhalation. 【Methods】 120 children diagnosed with RSV bronchiolitis were randomly divided to atomizing group and common group.The number of pant days during the acute and recovery stage,hospitalization days and recurrence cases of these two groups were recorded and compared.The blood serum eosinophilic cationic proteins (ECP),IL-6,IL-8 and IL-10 during the acute and recovery stage were tested and compared between the two groups,and statistics analysis was carried out. 【Results】 There was statistics significance (P＜0.05) of the pant days,hospitalization days and recurrence cases compared between these two groups.The values of ECP,IL-6 and IL-8 in the acute stage were higher than those in the recovery stage(P＜0.05).The value of IL-10 in the acute stage was lower than in the recover stage (P＜0.05).The difference had statistics significance (P＜0.05) between the above said test results in the recovery stage of the atomizing group and common group. 【Conclusion】 Budesonide atomizing inhalation has significant effects in treating RSV bronchiolitis,and certain effects in preventing post-infection inflammation of air passage.